Archive for ' Android'

Android NFC tag reader app update

We are proud to announce that our free NFC tag reader app has now been downloaded more than 10,000 times!

The app allows you to identify the type of tag you are scanning, and provides you access to non-secure information on Mifare cards.

Planned development involve currently support for Desfire, so watch out for an app update in the new year!

We also welcome any suggestions for improvements, so feel free to contact us directly with your requirements.

The NFC tag reader can be downloaded for free from Google Play here.

New app released – 600 raisons de ne pas voter Sorkozy (with Rue89)

We are pleased to announce that we have released a new app last week!

Rue89 - 600 raisons de ne pas voter Nicolas Sarkozy

The app is based on an extremely well-documented article published in the online French newspaper Rue89 listing 600 reasons not to vote for Nicolas Sarkozy for the French presidential election taking place in April/May 2012. The newspaper listed these reasons, and provided also links to articles, books, videos, on the web where the justification could be found.


We teamed-up with Rue89 to design and develop an app based on this, Rue89 providing the content in the form of a database, and Lothringer designing and publishing the resulting app.

You can browse the reasons, either randomly or using the next/previous buttons. For each of these reasons, you can tap on the associated link, and read the relevant article, or watch the video. More importantly, you can share the reasons you like on Facebook and Twitter!

You can visit our page dedicated to this app here.

This app has already been published on the Android Market, and is in the process of being published on the Apple iStore.

Update to our Number Properties app – Ulam’s Spiral

Our Number Properties app was released a few weeks ago, and we have finally found the time (during our Christmas break!) to tweak it. More details about this Android app can be found on its dedicated page.

Ulam's spiral - step 1

Amongst some minor improvements (slightly faster Sieve of Eratosthenes!), the main addition to this version is the capability to draw Ulam’s spiral.

It’s a really interesting way to graphically represent the distribution of prime numbers. You start by writing down the numbers in a spiral way.

You then either highlight the prime numbers, or delete the non-primes, and you obtain a spiral pattern with only some numbers visible.

Ulam's spiral - step 2

We’ve applied this to the app, and after calculating the maximum square that can be occupied by the diagram (depending on your screen resolution), we associate each number to a pixel, and draw each prime number with a certain colour, leaving out the non-primes. On a Samsung Galaxy SII, that’s roughly 282000 numbers.

Screenshot - centre on 1


Screenshot - centre on 52114


As you can see from these screenshots, when expanding to larger numbers, patterns start to emerge, mainly diagonal lines.

Changing the starting point of the spiral also shows identical patterns (here, the starting point is 52114), but an overall different picture.

You get some more information about the spiral (number of primes, etc) and can also change the origin, from the menu inside this activity.

This Android app is available for free on the Android Market, so enjoy :-)

Non-linear activity flow in an Android app

I have been facing this particular problem in one demo android app I am working on at the moment. The problem is that when the flow of activities in an Android app is linear, then the back button in Android is more than enough to get back to the previous activity. But when the flow is more convoluted, then using “back” or re-launching activities is not the best solution.

For instance:

Android activities linear flow

In this diagram, the flow we want is simple: we can only go from one activity to the next one, and in that particular instance, A launches B, which launches C, etc, and “back” is used to go back to the launching activity.

The situation I’ve had to resolve was slightly more complicated:

Android activities non-linear flow

In this example, we want to go from B to C to D to B as many times as we want, and when done, from B, get back to A by using the Android “back” button. And this is where I faced a problem: pressing “back” from B led me back to D, then C, etc etc.

I didn’t want to implement a cumbersome activities “breadcrumb” system, where each activity that is launched knows the history of its predecessors. So I came up with a simple solution: instead of going from D to B, why not go back from D to C, then C to B?
But in that case, what to do with C, since the user is not supposed to to see it again?

Well, my solution was to remember my Android Activity state machine, and implement an often overlooked method for Activity B; this is what happens (solution highlighted):

Android activities non-linear flow resolved

  1. B creates C
  2. C creates D
  3. D finishes (calls finish())
  4. the Android Activity manager automatically brings back to the front the activity that launched D, i.e. C
  5. C is then resumed, so by calling finish() in C’s onResume() method, C will terminate
  6. the Android Activity manager automatically brings back to the front the activity that launched C, i.e. B

For the user, it will look like we will go directly from D to B, and when in B, using the “back” button will bring us to A.

This might not be the best solution, but it works extremely well in my case, and I hope it will help someone else as well!

Number properties app released to Android Market

We have launched a new app yesterday on the Android Market. Being a kind of geek, it’s only normal that this app focuses on the properties of integers and the generation of prime numbers 😉

Number properties app icon

Find out more details about it on our dedicated number properties app page, and download it form the Android Market via this link.